diff --git a/CMakeLists.txt b/CMakeLists.txt
index a45f92f63..e94757cdf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -552,6 +552,7 @@ CHECK_FUNCTION_EXISTS(_atoi64 LWS_HAVE__ATOI64)
 CHECK_FUNCTION_EXISTS(_stat32i64 LWS_HAVE__STAT32I64)
 CHECK_FUNCTION_EXISTS(clock_gettime LWS_HAVE_CLOCK_GETTIME)
 CHECK_FUNCTION_EXISTS(localtime_r LWS_HAVE_LOCALTIME_R)
+CHECK_FUNCTION_EXISTS(gmtime_r LWS_HAVE_GMTIME_R)
 CHECK_FUNCTION_EXISTS(ctime_r LWS_HAVE_CTIME_R)
 CHECK_FUNCTION_EXISTS(getgrgid_r LWS_HAVE_GETGRGID_R)
 CHECK_FUNCTION_EXISTS(getgrnam_r LWS_HAVE_GETGRNAM_R)
diff --git a/cmake/lws_config.h.in b/cmake/lws_config.h.in
index ff3530842..d74679fa5 100644
--- a/cmake/lws_config.h.in
+++ b/cmake/lws_config.h.in
@@ -51,6 +51,7 @@
 #cmakedefine LWS_HAVE_EVP_PKEY_new_raw_private_key
 #cmakedefine LWS_HAVE_EXECVPE
 #cmakedefine LWS_HAVE_LOCALTIME_R
+#cmakedefine LWS_HAVE_GMTIME_R
 #cmakedefine LWS_HAVE_CTIME_R
 #cmakedefine LWS_HAVE_GETGRGID_R
 #cmakedefine LWS_HAVE_GETGRNAM_R
diff --git a/lib/roles/http/date.c b/lib/roles/http/date.c
index 5928d8cac..0b0012b6d 100644
--- a/lib/roles/http/date.c
+++ b/lib/roles/http/date.c
@@ -53,7 +53,14 @@ lws_http_date_render(char *buf, size_t len, const struct tm *tm)
 int
 lws_http_date_render_from_unix(char *buf, size_t len, const time_t *t)
 {
+#if defined(LWS_HAVE_GMTIME_R)
+	struct tm tmp;
+	struct tm *tm = gmtime_r(t, &tmp);
+#else
 	struct tm *tm = gmtime(t);
+#endif
+	if (!tm)
+		return -1;
 
 	if (lws_http_date_render(buf, len, tm))
 		return -1;
diff --git a/minimal-examples/secure-streams/minimal-secure-streams-sigv4/ss-s3-ss.c b/minimal-examples/secure-streams/minimal-secure-streams-sigv4/ss-s3-ss.c
index a9cce26df..b12f8f51c 100644
--- a/minimal-examples/secure-streams/minimal-secure-streams-sigv4/ss-s3-ss.c
+++ b/minimal-examples/secure-streams/minimal-secure-streams-sigv4/ss-s3-ss.c
@@ -87,15 +87,15 @@ create_payload(uint8_t *buf, size_t s)
 static void set_time(char *t)
 {
 	/*20150830T123600Z*/
-	time_t rawtime;
-	struct tm *info;
-
-	time(&rawtime );
-	info = gmtime(&rawtime);
-
-	strftime(t ,20,"%Y%m%dT%H%M%SZ", info);
-
-	return;
+	time_t ti = time(NULL);
+#if defined(LWS_HAVE_GMTIME_R)
+	struct tm tmp;
+	struct tm *tm = gmtime_r(&ti, &tmp);
+#else
+	struct tm *tm = gmtime(&ti);
+#endif
+	assert(tm);
+	strftime(t, 20, "%Y%m%dT%H%M%SZ", tm);
 }
 
 static void bin2hex(uint8_t *in, size_t len, char *out)